Multiplex radio telegraphy and telephony



Sept. 7 1926.

J- S. STONE MULTIPLEX RADIO TELEGRAPHY AND TELEPHONY Filed NOV. 30 1920 3 ShGVQtS-Sheef 1 mvemon Jvmflmfflm BY ATTORNEY Sept. 7 19.26.

J. S. STONE MULTIPLEX RADIO TELEGRAPHY AND TELEPHONY Filed NOV. 30 1920 3 Sheets-Sheet 2 E @ff ATTORNEY Sept. 7 1926. 1,598,663 I J. S. STONE MULTIPLE-'IX RADIO TELEGRAPHY AND TELEPHONY Filed Nov. 30 1920 3 Sheets-Sheet 5 Patented sept. 7, 1926.

narran stares rarer ortica.

JOHN sToNn sroNE, or sAN DIEGO, cLIronNrA, Assrenoa roar/IERICANTELE- PHONE AND rntnennrn COMPANY, a. cenreaanrroN or New Yoan.

Application led November 30, 1920. Serial No. 427,391.

The principle object of'my invention is to provide new and improved apparatus by which a number of messages may be transmitted or received simultaneously at a single station by radio telegraphy or telephony. Another object of my invention is to provide a plurality of pairs of balanced antennae or equivalent structures at a station, so positioned and adjusted that each pair may be conjugate to certain other pairs, and thus facilitate the simultaneous transmission and reception of messages. These and various .other objectsof my invention will.become apparent upon consideration of the following disclosure. The invention is defined in the appended claims, and a few specic'embodiments.are described in the following specification.

Referring to the drawings, Figure l is a perspective diagram showing two .conjugate pairs of antennae, one for transmitting, the other for receiving. Fig. 2 is a plan diagram that will be referred to in explaining Fig. 1 and other figures. Fig. 3 is an elevation showing another arrangement oftwo pairs of antennae. Fig. l is a plan diagram showing two pairs of antennae that are made conjugate by adjusting with coilsand condensers. Fig. 5 is a plan diagram showing how-a plurality of pairs of transmitting antennze and pairs of receiving antennae may j be made conjugate by adjustment with condensers. Fig. 6 is a plan diagram showing a space arrangement of more than two pairs of antennae to secure the desired conjugate relationship. Fig. 7 is a plan diagram showing a space arrangement that makes one pair of transmitting antennae conjugate to each of a plurality of pairs of receiving antennae. Fig. 8 ,illustrates an earth conduction system that may be employed in'- stead of a pair of aerial structures. Fig. 9 is a diagram that will be referred in eX- plaining the theory of one form of my invention and Fig. lO illustrates a modification to which reference will Vbe made.

In Fig. l the two transmitting antennae l and 2 are balanced against each other, that is, the transmitter T excites them equally and in opposite phase relation. In the equatorial plane of the transmitting antennae l and 2 stand the two receiving antennze 3 and 4c balanced against each other through the receiver R. gThe dotted lines in Fig.2 represent 'gequipotential surfaces,

around the respective transmitting antennae 1 and 2. At different times a particular line may represent different potentials, posi- `tive or negative; but any two points on the same line will always vbe at the same potential, whatever that may be. If 1 and 2 are transmitting antennae excited equally and 1n opposite phase relation, and if two other antennae, 3 and 4t, are placed on the mid-normal to the line joining l and 2 and balanced against each other, no current will be excited in them by the transmission from the antennae l and 2. This is the case shown in perspective diagram in Fig. `l. Y

But it is not necessary that the receiving antennae shall be limited to the equatorial piane; for, if they are balanced against each other, they may stand in other convenient relations as 8 and 4 or,.for example all four antennael l, 2, 3, 4L may stand in the same vertical plane, and this special casey is shown in elevation in F ig. 3. The necessary conditions to be satisfied will be stated presently. a

ln Figs. l and 3, I have shown the antennae open at vtheir upperends; but they may be closed across to form loops if desired, as indicated, for example in Fig. l,V

where the switches may be thrown down to complete the loops. f

As a convenient notation for the discussion that follows, I shall let the lower case letters c and m refer to the resultant capacities yandl inductances of the aerials whether or not supplemented or modified by added coils and condensers; and l shall use lupper case letters@ and M for condensers and coils added to the system for purposes of adjustment.v Thus the 0s and ms include the Cs and Ms. The positions ygiven the antennae in Fig. l are such that 013:02:01,:02,; where 013 represents the capacitybetween the two aerials l and 3 measured against` each other, and similarly for the other 0s. Also these arrangements satisfy the conditions mlszmwzmmzmg, 'where the ms represent mutual inductances between the respective antennae indicated by the associated sub-scripts. Furthermore, it is assumed in Fig. l that the four antennae are physically alike and equal, so that the conditions 01:02 and 03:04 will be satisfied, where these 0s represent the respective capacities of the aerials tov ground.

llVhen kthe i aerial kconductors are ..openbalanced transmitting antennae, l and 2, and,

a pair oiE balanced receiving antennae, 3 and 4. These/,are assumed to be positioned so that neither pair will be. vfound standing on a normal to the .line oining the other pair; hence an adjustii'ientor coriection by means of condensersor coils, or both, will be neces` sarj7 to secure the proper balance and conjugate. relation. Moreover, it may be as.- suined in Fig. 4 that` the antennae are not physicallyalike.A One maybe tallerthan another, or have a ydiil'erent overhead struct-ure from another g; and such diiierenees Will '.re quire adjustmentv with condensers or coils, or both, to secure the proper` balance and conjugate relation. If the antennze of Fig. 4 Wereall equal, and `if the conjugate relation were secured by positioning them, the equations4 among the 0s and ms previously Written out Would be satisfied; but since in the system of Fig. 4 these conditions are assumed not to exist, theJ discrepancies must be compensated'torand the balance and conjugate relationship secured by the addition of suitable eondensers and coils, as indicated inthe diagram.

It is assumed, -to make the illustration definite, that aerials l. and' 3 have somewhaty less capacities to ground than 2 and 4, and therefore suitable correction is made byadding the condensers C, and Us So as to make 01:02 and 03:0, Where` as previously explained, the lower case cs are resultant values. The capacities of the tivo condensers C14 and. C23 are made such as to compensate for the greater proximity of conductors l to 3 and 2 to 4, compa-red to that lolf conductors l to 4 and 2 to 3, respectively. Similarly, the mutual inductanees of the tivo transformers WM, M,1 and M23,-M32 are made such as to compensate tor the greater proximity of the conductors] to 3 and 2 to 4, respectively, compared to that o'tl to 4 and 2 to' 3.

From the foregoing discussion of Fig. 4, it will be seen `that the balancing' of the transmitter and receiver systems, as Well as the establishment of the conjugate relation between them, may be secured by the pro-per additionl oi' coilsV and condensers, and that this may be done inl general, no matter what arethe constants of the vaerial conductors, and no matter What is the space relation bet-Ween them. 9 is a diagram illustrating another form of connection for the 4- aerials which constitute the aerial system. The branches 12 and 34 may be most conveniently made conjugate `by the relation We have already given of 01,:02:01,:024e when 01:02 and 03:04. But When it is only necessaryto prevent currents developed in the branch l2 from aecting the branch 34, then it sutlices to establish the relations 013:02`3 and 014:024. The case of Fig. 3 is now seen tobe a special case under Fig. 4.

` Thus far I have considered only two conjugate systems, a transmitting pair and a receiving pair, vbut I Will noiv proceed to show hottT -aFlaiger number of pairs of antennae maybe .balanced and rendered conjugate for multiplex transmission and receiving of In Fig. 5 it is assumed tliattlie transmitting pair 1,'2 and the receiving pair 3, 4 are respectively balanced and made conjugate, either by being suitably positioned or by a supplemental `adjustment as indicated in the iforegoingr iscussion. sumed that the transmitting pair 5, 6 and the receiving pair 7, 8 are respectively balanced and made conjugate `inthe same Way. VIt remains todiscuss the relations that must be sustained between the elements l., 2, 3 and 4 ontlie one hand and, 6, 7 and 8. on the other hand to get. the necessary conju- ,gate` relationship for simultaneousV operation.

In general, to render` any one of the .re-

ceivers immune from interference `by any one of the transmitters` requires the conditions to be established that 01,.,:0r'l1 and 01,5:0rs

Where p and 7 represent the tWoy aerials of a pairs absolutely conjugate lso that either may be used as transmitter. While the other is used as receiver mayA beV effected yadvantageously by making Exempliiying the.l general equations (l) in connection Witli'Fig. l5, Wemust make '017:027 and.018:028. This. Will make the receiver 7-8 immune to the transmitter1 2l In order-tomake the Vreceiver 3 4 immune tothe transmitter 5-6, the special cases ot equations (l) must be satislied as follows: 035:045 and v@6:04p f l The condensers shown in Fig. 5 Without reference characters arc provided so'that these four equations may be established by Vgiving thosel condensers the proper capacity'values.

In general, `it will vnot be necessary to make the receiver systems (such as3-4 and 7 8 in Fig. conjugate with` each other. They-Willbeftuned differently and, .there- It is alsohas- `i kill fore, they can receive simultaneously without interference. Neither will it always bek necessary to makethe transmitter systems conjugate with each other. But it it is deemed necessary, this can be accomplished by giving suitable values to the condensers designated C2G, G25 and C,G in Fig. 5. Whatever the capacity between aerials 1 and 5, which we represent as 015, the condensers just mentioned can be given suitable values to satisfy the equations 015:0,6 and 025:026. Since it will usually be unnecessary to make the transmitter systems conjugate with each other, these last equations will not need to be satisfied except in special cases and the system oi Fig. will usually require only that the conditions indicated by equations (l) shall be satislied.

Although I have explained in connection with F ig. 5 how suitable adjustment and correction may be made for a quadruplex system, it will be evident that by similar methods the capacity ot the station can be increased tor multiplex work of higher or der. Thus another pair ot transmitting aerials 9, l() and another pair of receiving aerials il, 12 might be added to the system ot Fig.v 5, in which case the conditions given in equations (l) and (2) would still be applicable.

is in the simpler cases given, it isnot necessary in general to establish the conjugate relation between a transmitter and another transmitter, nor between a receiver and another receiver, it will generally only be necessary to establish the relations indicated by 'the equations (l). By extending this same method, any number of transmitters and receivers may be grouped at a given station.

In Fig. 5 I have shown how more than one transmitting pair and one receiving pair may be assembled at a station by the introduction ot adjusting elements to establish a proper conjugate relationship. The same object can be attained by positioning the antennae properly, as shown in the diagram ot Fig. 6. Here the transmitters l, 2; 5, 6; and 9, are each in conjugate relationship with each ot the receiving pairs 3, 4; 7, 8; 1l, l2 by virtue of a space relation. In this case all the transmitters are disposed in one vertical plane having a common equatorial plane, and all the receivers are disposed in this common equatorial plane and vice versa, thus the desired conjugate relationship between any transmitter and any receiver is secured.

In Fig. 7 a single transmitting pair l, 2 is shown with a plurality ot receiving pairs 3, 4; 5, 6; 7, 8, all in the equatorial plane of the transmitter. Thus three messages might be received simultaneously by the three receivers without interference from the one transmitter.

November 1920.

In a set ot antennae such as here disclosed, it may be desirable and practicable to replace one or more of them by an' artiiicial aerial'or a plurality of such aerials. Fig. 10 illustrates a modilication of Fig. 3, in which two ot the tour aerials of Fig. 8 have been replaced by artilicial aerials.

By the term antenna in the following claims I include any equivalent structure. Thus a pair ot aerials may be replaced by an earth conduction system as illustrated in Fig. 8, where E and F are two conductive plates connected by conductors laid in the subterranean conduit H. These conductors lead through the transmitting or receiving apparatus G. Y

What I claim is :-n

1. A radio transmitting and receiving station having a plurality of pairs of balanced transn'iitting antennae and a plurality ot pairs of balanced receiving antennae, each transmitting pair being conjugate with each receiving pair.

2. A radio transmitting and receiving station having a plurality ot pairs ot balanced transmitting antennae and a plurality of pairs ot balanced receiving antennae, and current influencing elements interposed between the antennae to secure adjustment thereof to make each transmitting pair conjugate to each receiving pair.

3. A radio transmitting and receiving station having a pair of balanced transmitting antennae and a pair oi balanced receiving antennae, said antennae being not all equal, nor equidistant Afrom the members ot the other pair, and connections from one pair to the other comprising coils and condensers to perfect the balance between them and to make each pair conjugate to the other pair.

4. 'A multiplex radio transmitting and receiving station having transmitting pairs ot antennae and receiving pairs spaced apart, and coils and condensers interconnecting certain members of the pairs, the members of each pair being balanced against each other, each transmitting pair being made conjugatey with each receiving pair by means of said coilsand condensers.

5. A multiplex radio .transmitting and receiving station having transmitting pairs of antennae and receiving pairs spaced apart, and coils and condensers interconnecting certain members of the pairs, the members ot each pair being balanced against each other, each transmitting pair being made conjugate with each receiving pair by means ot said coils and condensers and eachy transmitting pair being made conjugate to each other transmitting pair by means of said coils and condensers.

In testimony whereof, I have signed m iio name to this specilication this 18th day of JOI-IN STONE STONE. 

